🦖 rexrex

Regular Expression utils that rock!

Create regular expressions that are composable, reusable, and commentable.

Getting started

yarn add rexrex

Utils

whole

whole('sentence to match') // -> ^sentence to match$

repeat

repeat('\\d') // -> \\d
repeat('\\d', 8) // -> \\d{8}
repeat('\\d', 1, 3) // -> \\d{1,3}
repeat('\\d', 1, Infinity) // -> \\d{1,}

numeric

Equivalent to rex.repeat.bind(null, '\\d')

alpha

Equivalent to rex.repeat.bind(null, '[A-z]')

and

and('a', 'b', 'c') // -> 'abc'

or

or('a', 'b', 'c') // -> 'a|b|c'

wildcard and extra

wildcard('.') // -> '.*'
wildcard('.', true) // -> '.*?'
extra('.', matchers.LAZY) // -> '.+?'
extra('.', false) // -> '.+'

capture

capture('\\d+?') // -> (\\d+?)

or you can name your capture group with capture(pattern, name)

capture('\\d+?', 'number') // -> (?<number>\\d+?)

group

Similar to a capture(...), but won't keep the capture within the parentheses

group('.|\\s') // -> (?:.|\\s)

look.(ahead|behind).(positive|negative)

Creates a negative or positive look-ahead

look.ahead.positive('Y') === look.ahead('Y') // -> '(?=y)'
look.ahead.negative('Y') // -> '(?!y)'
look.behind.positive('Y') === look.behind('Y') // -> '(?<=y)'
look.behind.negative('Y') // -> '(?<!y)'

regex

Equal to RegExp constructor

Matchers

• ALPHA: '[A-z]'
• WORD: '\\w'
• NUMBER: '\\d'
• WHITE_SPACE: '\\s'
• ANY: '.'
• START: '^'
• END: '$'
• LAZY: '?'

not

Matches opposite of matchers

regex(matchers.not.ALPHA) // -> '[^A-z]'

Flags

• GLOBAL: 'g'
• MULTI_LINE: 'm'
• INSENSITIVE: 'i'
• STICKY: 'y'
• UNICODE: 'u'

Examples

See index.spec.js for all the uses!

// found in `graphql-types-drivers-license`

// Matches all New York Driver's licenses
regex(
  or(
    and(alpha(1), numeric(7)),
    and(alpha(1), numeric(18)),
    and(numeric(8, 9)),
    and(numeric(16)),
    and(alpha(8))
  )
)
// -> /[A-z]{1}\d{7}|[A-z]{1}\d{18}|\d{8,9}|\d{16}|[A-z]{8}/

// matches GraphQL queries/mutations

regex(
  and(
    capture(
      and(
        capture(or(...GQL_TYPES)),
        extra(SPACE),
        extra(WORD),
        extra(SPACE),
        wildGroup(and('on', extra(SPACE), extra(WORD)))
      )
    ),
    wildcard(SPACE),
    wildGroup(
      and(extraGroup(and('{', extraGroup(CHARS))), extraGroup(and('}', extraGroup(CHARS))))
    ),
    '}'
  ),
  flags.GLOBAL
)

// -> /((fragment|query|mutation|subscription)\s+\w+\s+(on\s+\w+)*)\s*(({(\s|\w|(".*")|:|,|\.|\)|\()+)+(}(\s|\w|(".*")|:|,|\.|\)|\()+)+)+}/g

Bonus

• Tiny!
• Super-readable!
• Changes make sense!